If you could offer the proponents of these laws a deal where all the bills die in committee and in exchange Pornhub gets shut down, I suspect they'd take it. But you can't. The First Amendment doesn't permit such targeting, and almost nobody who opposes age gating would concede the premise that porn is inherently bad.
But again, the problem isn't this or that content-exchange site; the problem is people doing illegal activities within, or facilitated by, such sites, or people within the site that are sourcing willingly illegal material or distributing material that is illegal to some recipients. And lawmakers are targeting the middlemen and the recipient instead of going to the root cause, and the cynic in me thinks, "Of course they'd do that, why would they go after themselves?" But it's a bit of a reduction, and not all wolves are rich and powerful (though those who are uncaught or get away scot-free mostly are).